The milling processes from which the wheat germ fraction is recovered are well established and familiar to the wheat milling industry. Generally, the isolated wheat germ constitutes about 2 percent of the weight of the processed wheat. This fraction, also known as the embryo of the wheat, will assay about 9.5 percent wheat germ oil, and about 27-29 percent protein (N.times.6.25). The wheat germ oil is a source of Vitamin E.
When freshly toasted, wheat germ has a pleasing nutty flavor. This nice flavor coupled with the nutritive aspects associated with wheat germ, make it an attractive health food. Despite the recognized features of nutrition and flavor, wheat germ has one negative which is also well known. It may become rancid in a short time if it is left unrefrigerated. Sometimes this rancidity, or off-flavor, occurs in as short a time as three or four days. This poor shelf-life has been observed even with wheat germ packaged in sealed glass jars, with a nitrogen purge to eliminate air, and evacuated after filling. The product labels often advise refrigeration of the jars containing wheat germ after they are unsealed. Even if refrigerated, its shelf life is less than desirable and needs to be improved.
One of the objectives of this invention is to process wheat germ, or other cereal seeds, so as to improve its shelf-life, or stability at ambient temperatures, to as much as at least seven to eight months or even more.
Another objective of this invention is to achieve this outstanding degree of stability without the use of chemical additives.
Another object of this invention is concerned with packaging the processed wheat germ.
Another object of this invention is to process wheat germ to eliminate sulphydryl (SH) to an extent sufficient that it may be a useful ingredient in bakery products without adversely affecting the flour glutens.
The techniques for achieving these objectives, and others, will become apparent from the following description of this invention, which will be detailed with reference to and exemplified by a process for the improvement of wheat germ and by the wheat germ product produced thereby. It should be recognized that, although wheat germ will have been used to illustrate the practice of this invention, it is by no means a limitation upon the utility and applicability of the invention hereof.
In U.S. Pat. No. 3,519,441, "Process for Treating Flour and Starch to Eliminate Free SH Groups," issued to Ferrara et al., the art taught therein shows that the elimination of sulfhydryl groups (SH) in wheat germ achieves a prolongation of shelf-life. This patent showed that steaming wheat germ for 35 to 50 minutes was adequate, in most cases, to produce a product which had improved shelf life in that rancidity was avoided for longer than had been possible in the past. It was found that longer intervals of steaming resulted in the loss of the nutty flavor usually associated with freshly toasted wheat germ. (See Column 8, Lines 70-75). In this patent, the tests which had been run allowed little steam to escape. In column 9, lines 4-10 it is stated: "There appears to be a slight but noticeable difference in the SH and the enzyme activity...between wheat germ meals made from different wheats, etc.".
In the processes of U.S. Pat. No. 3,519,441, to insure the pressure in the cooker was maintained at a constant pressure, a small amount of steam was allowed to escape. Since allowing steam to escape was for control purposes, the amount of steam which was allowed to escape was kept to a minimum. The steam which did escape from the toaster smelled like cooked wheat germ. No attempt was made to determine the amount of escaping steam since it was not considered to be a substantial variable in the process. It was believed that the shelf life of the product wheat germ was a function only of the amount of SH elimination and not the way in which the SH elimination was accomplished.